You won't dig this answer about your grass woes

COMMENTARY - Plant Doctor

Question: Bermuda grass is taking over my St. Augustine lawn, and I am trying to dig it out or spot-kill it in the dense areas. Is there a way to get rid of it?

Answer: Good buddies, that is what you might call these lawn types, and it's about impossible to separate one from the other. Regretfully, digging out the Bermuda grass is going to be about the least effective method, unless you can remove a square that includes the St. Augustine, too.

Spot-killing patches is probably the best way to eliminate the Bermuda grass. Often, however, even this is not effective because some runners often remain dormant in the ground to avoid the sprays. You might apply the spray and then wait a week or two to see if any Bermuda grass regrows; if so, retreat before sodding in yet a few more weeks to renew the lawn.

Get Bahia going

Q: I have a thin Bahia lawn that I want to re-establish. When and how can I reseed, and should I spray the weeds now?

A: Good Bahia-growing weather has just arrived, so schedule the seeding anytime between now and the end of summer. Control the weeds as needed with a nonselective herbicide that allows sowing after the unwanted vegetation declines. Good soil preparation is then the trick to establishing the lawn.

Start by removing the weedy debris and loosening the soil. At least rake the soil an inch or so deep or better yet till it 4 to 6 inches deep. Rake the site smooth, and adjust the soil acidity if needed and apply a light fertilizer application. Sow the Bahia seed and rake it to a half-inch deep in the ground or cover with weed-free soil.

Keep the soil moist, and the seeds should begin to germinate within two to three weeks. Continue to water when the surface begins to dry until the turf grows roots deep into the soil. Also apply a fertilizer when the grass is 2 inches tall, and mow as needed to maintain a height of 3 to 4 inches. Most likely, weed control is also going to be needed after two or three mowings.

The mighty mites

Q: The rose bushes I have loved for four years have small bugs on the bottom of the leaves that are making them look terrible; they were supposed to be pest-free plants. How can I fix this problem?

A: Pest-free in this case is more of a wish, as it is with most plants. Eventually, they all seem to succumb to some critter, and your roses have mites. These are mainly dry-time pests that feed on the undersides of the leaves by sucking out their juices. This gives the foliage the yellow look.

Gardeners have for years washed away these pests with a strong stream of water directed onto the mites. Some people seem to be better than others at eliminating these pests this way. If you need a pesticide, a natural insecticidal soap or horticultural oil spray also can be effective. You still have to hit the mites with the spray on the undersides of the leaves to obtain good control.

Oil vs. soap

Q: My bird of paradise seems to have scale constantly, and I control it with horticultural oils. If I make a soap spray, would it work better? And what can I do to keep the soap spray from burning the plants?

A: Homemade mixtures are unknowns when it comes to plant safety, and many gardeners report damage from concoctions formulated in a sink. Perhaps to keep toxicity to a minimum, it would be best to purchase a brand-name product with a proven plant-safety record.

Soaps can be used for scale control, but you have to hit the insects in the crawler stage. When it comes to scale control, the horticultural oils seem to be the most effective of the natural products because they are active against all stages. Several good brands are available at your local garden centers.

Prune azaleas ASAP

Q: The azaleas have grown large and wide in my yard. Is now a good time to prune?

A: Complete azalea pruning as soon as possible. When summer arrives, the plants begin forming flower buds for the following spring. It won't harm the plants if you delay the pruning, but you could miss a good flower show.